A file photo of the exterior of the front entrance University Medical Center at Princeton on Witherspoon Street. Michael Mancuso/The Times

PRINCETON TOWNSHIP — An independent review of whether the developer hoping to build a 280-unit apartment complex on the former University Medical Center of Princeton site adequately tested the area for potential environmental hazards was recommended by the Princeton Environmental Commission tonight.

The advisory group met tonight to discuss the building application from developer AvalonBay, which will go before the full planning board tomorrow night in the first of most likely a series of meetings to determine whether the company will be permitted to build the complex.

The recommendation by the Environmental Commission suggested that the septic system on the site may not have been fully investigated and mentioned that there are active underground tanks on the property.

A courtroom-like drama played out at the meeting as the commission, a representative from the potential developer AvalonBay and the attorney for the citizen’s group Princeton Citizens for Sustainable Neighborhoods loudly and passionately argued over whether there was evidence showing potential contamination on the site, if Avalon had done enough to ensure there are no issues there and whether it was Avalon’s responsibility to definitively prove the site is environmentally sound at this time.

The crux of the issue revolved around a report conducted by Ecolscience, the consulting group Avalon hired to investigate any potential environmental hazards on the site. The report recommended five areas for the developer to look at more closely, including sewer discharge, underground storage tanks and facility decommissioning requirements.

Avalon representative Anne Studholme argued that the report, which was completed in September 2011, was meant only to inform the developer if there were any major issues with the area before Avalon purchased the site. However, she said a second study by Ecolscience found there were no environmental problems at the site.

The Environmental Commission decided to recommend that the planning board require that Avalon test the soil at the site for potential contamination and have an independent environmental expert come in and review whether Avalon has properly examined conditions there.

The commission said Avalon must get soil and/or ground water testing either now, before approval or during construction — at its own expense.

Studholme repeatedly said that there was no evidence of contamination at the hospital site and that if something were to be discovered during the construction of the complex, the state Department of Environmental Protection would immediately step in.

Still, members on the board were wary of those arguments, insisting that the property may not have been satisfactorily investigated by Avalon.

The meeting marked the second time this month that the group discussed the Avalon application. In an early October gathering, the commission members declined the request of citizen’s group Princeton Citizens for Sustainable Neighborhoods to require Avalon to pay for additional environmental testing on the site.

Citizens for Sustainable Neighborhoods argued at the time that Avalon had failed to report certain potential hazards in an environmental impact statement that was submitted as part of the developer’s site plan, such as four underground tanks on the property. Hospital representatives at that meeting denied that there were any outstanding environmental issues on the property and Avalon representatives said they had done all the testing asked of them at the time